1. Field of the Invention
This invention relates to cable attachments and, more particularly, to an insert for a cable thimble.
2. The Prior Art
Cables are referred to in the art as wire ropes and find wide application throughout the world in various applications where there is a requirement for transmitting tensile forces, providing stability or otherwise providing tension in a structural device. When used as a stabilizing member or in a guy wire configuration, any tendency for a cable toward elongation produces a detrimental effect on the object being stablized. For example, cable elongation in a sailboat, hang glider, antenna, tower or the like results in a corresponding degradation in structural integrity.
Cable attachment is by means of a loop interconnected with an anchor, or the like. Frequently, the loop is formed by bending the cable about a device known in the art as a thimble. The thimble is fabricated from a strip of metal formed with a semicircular cross section and bent longitudinally into a tear drop-like profile. The channel formed by the semicircular cross section faces outwardly and receives the cable engaged with the thimble. The cable is suitably swaged to lock the cable about the thimble thereby producing a thimble eye. Of course, prior to fabrication, the thimble eye is interconnected with the anchoring device. A thimble eye formed about a thimble provides a relatively compact loop of known dimensions. However, under conditions of stress the thimble is known to collapse and elongate slightly resulting in an elongation of the thimble eye. Elongation of any part of the cable results in a corresponding loss of trim to the overall structure. In sailboats, hang gliders and the like, this loss of trim is most undesirable and has been a source of dissatisfaction in the trade.
Additionally, for those devices that are frequently disassembled and reassembled, such as hang gliders, binding of thimble on tang in a misaligned position frequently occurs in the cable at the interconnection between the thimble eye and the tang. This binding or tangling results from the thimble eye being freely movable over a substantial portion of the tang and results in an undesirable degree of twisting and tangling of the cables. Cable twisting or kinking is particularly undesirable since a severe kink drastically reduces the tensile strength of the cable resulting in its required replacement.
One prior art technique for reducing the tendency for a cable to kink at the interconnection with the anchor has been to envelope the thimble eye and anchor in a length of heat-shrink plastic tubing followed by heating to shrink fit the plastic about the thimble eye and anchor interconnection. However, this technique does nothing to inhibit elongation of the thimble eye.
It would, therefore, be a significant advance in the art to provide an apparatus and method for inhibiting thimble elongation and cable tangling. It would also be an advancement in the art to provide a thimble insert which may be readily inserted into an existing thimble eye. Such an apparatus and method is disclosed and claimed herein.